Fluid flow control device

ABSTRACT

A fluid flow control device is inserted in the vacuum lines connecting the carburetor spark and manifold vacuum ports to the ignition distributor adjusting servo actuator, the device having a number of orifices and one-way check valves to provide a different slow rate of pressure equalization during decelerations than during accelerations, for good performance as well as emission control.

U Unlted States Patent 1 1 1111 3,920,041

Gropp 5] Nov. 18, 1975 [5 FLUID FLOW CONTROL DEVICE 3,678,907 7/1972Vartanian 123/117 A 3,698,366 10/1972 Gropp v 123/117 A [75] lnvemor'Karl j Grosse pome 3,730,154 5/1973 Vartanian 123/117 A Woods, Mich.

[73] Assignee: Ford Motor Company, Dearbom, m y Examiner-Robert Gr iISMich. Attorney, Agent, or FirmRobert E. McCollum; Keith 22] Filed: Nov.5, 1973 Zerschlmg [21] Appl. No.: 413,136, [57] ABSTRACT A fluid flowcontrol device is inserted in the vacuum 52 us. c1. 137/599; 123/117 A;137/5121 lines connecting the Carburetor Spark and manifold 51 1111.(:1. F02P 5/10 vacuum ports to the ignition distributor adjusting [58]Field of Search 123/1 17 A; 137/] 10, 5121 servo actuator, the devicehaving a number of orifices 137/599, 5991 and one-way check valves toprovide a different slow rate of pressure equalization duringdecelerations than [56] References Cit d during accelerations, for goodperformance as well as UNITED STATES PATENTS em'lsslon control'3,572,363 3/1971 Roach 137/110 5 C 4 Drawing Figures ,6 2) 32 Er" I o 36US. Patent Nov. 18, 1975 0d ww w\ MM WW pm w. ax w\ w. Q w o 0 mm .m. NMI I o w H \M Q H l v h A N wk (HO 7. N0 E A -NN- M R @N mm Q 9% Q\ Nvw\a/\ FLUID FLOW CONTROL DEVICE This invention relates in general to anengine spark timing control; More particularly, it relates to one inwhich the rate of change of spark timing can vary between heavy vehicleaccelerations and decelerations, for improvedemissions and engineperformance.

This invention is an improvement over the quick recovery spark timingcontrol system shown in US. Pat. No. 3,698,366. The latter shows a sparktiming control system in which a vacuum servo controlled by bothcarburetor spark port and manifold vacuum advances the ignition timingin opposition to a spring normally biasing the timing mechanism towardsa retarded position. The vacuum line between the carburetor spark portand servo includes an orifice so that relatively slow vacuum changesduring light vehicle accelerations will only be slowly communicated tothe servo; likewise, decelerations will cause only a slow bleed of thevacuum from the servo to the spark port. As a result, a rapid recoveryof the spark setting is provided upon light reacceleration after amomentary deceleration. It will be noted that the rate of decelerationchange in vacuum, however, in this'case is the same as the accelerationrate. Accordingly, the point at which reacceleration occurs may not bethe most desirable ignition timing setting for engine performancepurposes; also, the use of such a single device with a controlled rateof bleed restricts the device to particular characteristics.

It is an object of the invention, therefore, to provide a device of thetype described above in which, however, a different rate of change ofspark timing is provided at times for vehicle accelerations as comparedto decelerations to provide a more selective control of the ignitiontiming and to improve the performance over that provided in US. Pat. No.3,698,366.

The invention accomplishes the above objectives by providing anadditional flow restriction device in series with a one-way pressurerelief valve in a line bypassing a flow restriction between thecarburetor spark port and the servo actuator adjusting the engineignition timing, and operable in response to vehicle decelerations toprovide a different rate of pressure equalization between the carburetorand servo actuator than during vehicle accelerations.

It is also an object of the invention to provide a spark timing controldevice providing a rapid recovery of the spark timing setting after amomentary vehicle deceleration, and one that provides improvedperformance by the spark timing being set more accurately or closer tothe setting most desirous for the acceleration desired.

It is a still further object of the invention to provide an enginevacuum spark timing control device located between the carburetor sparkport and the servo adjusting the ignition timing that at times providesa rate of equalization of pressures during decelerations that is fasterthan the rate of vacuum change during accelerations so that the sparkadvance setting moves more rapidly towards a retarded setting to providethe desired setting upon reaccelerations.

Other objects, features and advantages of the invention will become moreapparent upon reference to the succeeding detailed description thereof,and by reference to the drawings showing the preferred embodimentthereof, wherein;

FIG. 1 illustrates schematically a known spark timing control shown inUS. Pat. No. 3,698,366;

FIG. 1A graphically illustrates changes in spark vacuum or advance withtime for the construction shown in FIG. 1;

FIG. 2 illustrates schematically a spark timing device embodying theinvention; and,

FIG. 2A graphically illustrates changes in spark vacuum or advance withtime of the device embodying the invention as compared to that shown inFIG. 1A.

FIG. 1 shows, schematically, a construction shown and described in theprior art in US. Pat. No. 3,698,366. Only those portions of an internalcombustion engine that are normally associated with the enginedistributor spark timing setting control are shown, such as a carburetor10, a distributor breaker plate 12, a vacuum servo 14 to control themovement of breaker plate 12, and a line 16 between the carburetor andvacuum servo to automatically change the engine spark timing setting asa function of changes in carburetor vacuum spark port setting.

More specifically, carburetor 10 is shown as being of the downdraft typehaving the usual air/fuel induction passage 18. It has an atomsphericair inlet 20 at one end and is connected to an engine intake manifold 22at the opposite end. Passage 18 contains the usual fixed area venturi 24and a throttle valve 26. The latter is rotatably mounted on a part ofthe carburetor body across passage 18 in a manner to control the flow ofair/fuel mixture into the intake manifold. Fuel would be inducted in theusual manner from a nozzle, not shown, projecting into or adjacentventuri 24, in a known manner.

Throttle valve 26 is shown in its engine idle speed position essentiallyclosing induction passage 18, and is rotatable to a nearly verticalposition essentially unblocking the passage. A spark port 28 is providedat a point just above the idle position of throttle valve 26, to betraversed by the edge of the throttle valve during part throttle openingmovements.'Thiswill change the vacuum level in spark port 28 as afunction of the rotative position of the throttle valve, the spark portreflecting essentially atmosphericpressure in the air inlet 20 uponclosure of the throttle valve. An intake manifold vacuum sensing port 30is also provided, for a purpose to be described.

As stated previously, the distributor, not shown, includes a breakerplate 12 that is pivotally mounted at 31 on a stationary portion of thedistributor, and is movable with respect to a cam 32. The latter haspeaks 34 corresponding to the number of engine cylinders. Each of thepeaks cooperates with the follower 36 of a breaker point set 38 to makeor break the spark connection in a known manner for each one-sixth, inthis case, rotation of cam 32. Pivotal movement of breaker plate 12 in acounterclockwise spark retard setting direction, or in a clockwise sparkadvance setting, is provided by an actuator 40 slidably extending fromvacuum servo l4.

Servo 14 may be of a conventional construction. It has a hollow housing42 whose interior is divided into an atmospheric pressure chamber 44 anda vacuum chamber 46 by an annular flexible diaphragm 48. The diaphragmis fixedly secured to actuator 40, and is biased in a rightward retarddirection by a compression spring 50. Chamber 44 has an atmospheric orambient pressure vent, not shown, while the chamber 46 is connected by abore, also not shown, to line 16.

During engine-off and other operating conditions to be described,atmospheric pressure exists on both sides of the diaphragm 48,permitting spring 50 to force the actuator 40 to the lowest advance or aretard setting position. Application of vacuum to chamber 46 movesdiaphragm 48 and actuator 40 toward the left to an engine spark timingadvance position, by degree as a function of the change in vacuum level.

The prior art spark control device in FIG. 1 includes a main vacuum line54 connected at one end to the carburetor spark port 28 and at its otherend to line 16. The line 54 contains a fixed area flow restrictingorifice 56, which delays the communication of a change in vacuum signalfrom one side of the restriction to the other at a rate according to thesize and characteristics of the orifice. FIG. 1A illustrates, forexample, a typical curve 58 showing the slow rise in vacuum level atservo chamber 46 upon opening of the throttle valve 26 exposing port 28more and more to manifold vacuum. The descending portion 60 of the curvealso shows the decay of vacuum at the servo chamber 46 at the same rateas the increase, during decelerations in which the atmospheric pressureat port 28 due to closing of the throttle valve only slowly bleeds downthe vacuum signal through orifice 56. This provides a more rapidrecovery to the previous advance setting than in conventionalconstructions in the event the throttle valve is again opened at somepoint prior to total bleeddown of the vacuum signal. In conventionalconstructions, closing of the throttle valve usually immediately strokesthe servo diaphragm to the lowest spark retard setting.

The connection does contain a second or branch vacuum line 62 connectedat one end to the manifold vacuum port and at its other end to thevacuum line 16 in parallel with spark port line 54. Line 62 contains aspring closed one-way check or pressure relief valve 64 that opens onlyduring heavy vehicle accelerations to immediately drop the spark timingto a lower advance setting, for performance. That is, during heavyaccelerations, the manifold vacuum drops to nearly zero. The resultanthigh pressure overcomes the spring force of valve 64 to open the valveto immediately bleed the vacuum in servo chamber 46 to the same leveland drop the engine spark timing to the appropriate level for thisacceleration.

It will be noted from the above that in the prior art constructionillustrated by FIGS. 1 and 1A, the spark timing changes during lightvehicle accelerations and decelerations occur at the same rate, and thatthere is no latitude because of the fixed area of restriction 56providing these controls. Therefore, if after a slight deceleration inwhich the servo vacuum has not decayed to zero, if the vehicle is thenreaccelerated, the application of vacuum to the spark port 26 will thenthrough the orifice 56 readvance the spark timing along the curve shownat 66. This advance setting of spark timing setting, however, may not bethe most appropriate setting for the acceleration desired. That is,better performance may be obtained by having a lower advance setting,for example.

The invention accomplishes the above objective by providing a bypassline around the flow restricting orifice 56 so that the operatingcharacteristics of the quick recovery system can be varied, and the rateof change of vacuum during decelerations at times can be controlled tobe different than that during accelerations.

More specifically, as shown in FIG. 2, again, the spark control vacuumline 54 contains the fixed area orifice 56; and the manifold vacuum port30 is connected to the servo chamber 46 by the vacuum line 62 containingthe one-way check or pressure relief valve 64. However, in this case, abranch line is provided around the orifice 56 for bypassing the orificeduring deceleration operations. More specifically, the line 70 containsa second spring closed one-way pressure relief or check valve 72 inseries with a second fixed area orifice or flow restriction 74. In thiscase, during vehicle decelerations, when the spark port sensesessentially atmospheric pressure due to the closed throttle valve, orany pressure that is high enough to overcome the force of the spring ofvalve 72 and the pressure on the servo side of the valve 72, valve 72will open and provide a combined bleed of the vacuum at the distributorservo chamber 46 through both orifices 74 and 56. This is illustrated inFIG. 2A by the portion 76 of the curve having a steeper angle than thatshown at 60 in FIG. 1A. That is, the concurrent bleed of vacuum from thedistributor servo through both orifices provides a faster drop in theignition timing advance setting, and one that will provide the desiredoperation.

During light vehicle accelerations, the invention 0perates in the samemanner as the prior art in that slowly increasing vacuum in spark port28 causes the valve 72 to be closed by the higher pressure at thedistributor servo 46 and the valve spring so that the bleeddown of thepressure at the servo occurs now only through the orifice 56 providing arate of change of spark advance shown by the curve 58 the same as thecurve 58 in FIG. 1A. Likewise, heavy vehicle accelerations decaying themanifold vacuum to nearly zero level will quickly pop off the one-wayvalve 64 and provide atmospheric or nearly atmospheric pressure at theservo chamber 46 to immediately drop the timing advance setting to a lowadvance or fully retarded position.

From the above, therefore, it will be seen that the invention provides aspark timing control device that permits more selectivity in controllingthe rate of change of ignition timing during various phases of operationof the engine and provides greater performance capabilities thanpreviously provided by the prior art devices; also, the device of theinvention provides better emission control by providing a slow advanceof the ignition timing during light vehicle accelerations, with betterperformance and yet rapid recovery of the ignition timing if the lightvehicle accelerations are interrupted by momentary decelerations.

While the invention has been illustrated and described in its preferredembodiments, it will be clear to those skilled in the arts to which itpertains that many changes and modifications may be made thereto withoutdeparting from the scope of the invention.

I claim:

1. A fluid flow control device for use in a vacuum line connected to asource or pressure at one end varying between atmospheric andsubatmospheric levels and at its other end to a fluid chamber, thedevice including a first flow restriction delaying communication of apressure change at one rate from one side of the restriction to theother, a bypass line bypassing the first restriction and containingadditional flow restriction means and other means in series with theadditional flow restriction means rendering the latter operableconcurrent with the first restriction in response to a predeterminedchange in pressure on one side of the first restriction relative to thepressure on the other side, to provide at times a different rate ofequalization of pressures, a second line connected at one end to asecond source of pressure varying between atmospheric and subatmo- 4. Acontrol device as in claim 1, including means providing a controlledinterconnection between the first and second sources.

5. A control device as in claim 3, the further means check valve beingoperable at a higher predetermined pressure level than the other meanscheck valve for providing concurrent operation of the first andadditional restriction means at pressure levels between thepredetermined pressure levels of the other and further me ans.

1. A fluid flow control device for use in a vacuum line connected to asource or pressure at one end varying between atmospheric andsubatmospheric levels and at its other end to a fluid chamber, thedevice including a first flow restriction delaying communication of apressure change at one rate from one side of the restriction to theother, a bypass line bypassing the first restriction and containingadditional flow restriction means and other means in series with theadditional flow restriction means rendering the latter operableconcurrent with the first restriction in response to a predeterminedchange in pressure on one side of the first restriction relative to thepressure on the other side, to provide at times a different rate ofequalization of pressures, a second line connected at one end to asecond source of pressure varying between atmospheric and subatmosphericlevels and at its other end to the fluid chamber, and further means inthe second line operable in response to a predetermined pressure levelat the second source to immediately equalize the pressures at the secondsource and fluid chamber regardless of the operativeness of the firstrestriction and additional restriction means.
 2. A control device as inclaim 1, the further means comprising a one-way check valve.
 3. Acontrol device as in claim 2, the other means comprising a one-way checkvalve.
 4. A control device as in claim 1, including means providing acontrolled interconnection between the first and second sources.
 5. Acontrol device as in claim 3, the further means check valve beingoperable at a higher predetermined pressure level than the other meanscheck valve for providing concurrent operation of the first andadditional restriction means at pressure levels between thepredetermined preSsure levels of the other and further means.